The current research processes of electroplating and electroless Ni-P alloy plating on magnesium alloys were reviewed. Theoretically,the reason for difficulties in electroplating and electroless plating on magnesium a...The current research processes of electroplating and electroless Ni-P alloy plating on magnesium alloys were reviewed. Theoretically,the reason for difficulties in electroplating and electroless plating on magnesium alloys was given.The zinc immersion, copper immersion,direct electroless Ni-P alloy plating and electroplating and electroless plating on magnesium alloys prepared by chemical conversion coating were presented in detail.Especially,the research development of magnesium alloy AZ91 and AZ31 was discussed briefly.Based on the analysis,the existing problems and future research directions were then given.展开更多
A crystalline and non crystalline two phase Ni B coating was prepared by electroless deposition with potassium borohydride as reducing agent. When the deposit was heated from 10 °C to 500 °C , it took place ...A crystalline and non crystalline two phase Ni B coating was prepared by electroless deposition with potassium borohydride as reducing agent. When the deposit was heated from 10 °C to 500 °C , it took place three kinds of phase transformation and formed corresponding nickel borides. An Atomic Force Microscopy (AFM) was used to directly view the surface morphologies of the samples in various treated states. The AFM images indicate that nano dimensional protrusions grow on the surface of the deposit grain during some heat treatment processes, and they are distinguished greatly from the small bulges existing in the as plated deposit. Further studies show that the microhardness related to the surface topography of the coating to some extent. Especially when a two step heat treatment process was performed, the nano dimensional protrusions on the grain surface grew upt to 40～100 nm in diameter and 10～20 nm in height, and the deposit microhardness reached up to HV1500～1600 in the meantime.展开更多
文摘The current research processes of electroplating and electroless Ni-P alloy plating on magnesium alloys were reviewed. Theoretically,the reason for difficulties in electroplating and electroless plating on magnesium alloys was given.The zinc immersion, copper immersion,direct electroless Ni-P alloy plating and electroplating and electroless plating on magnesium alloys prepared by chemical conversion coating were presented in detail.Especially,the research development of magnesium alloy AZ91 and AZ31 was discussed briefly.Based on the analysis,the existing problems and future research directions were then given.
文摘A crystalline and non crystalline two phase Ni B coating was prepared by electroless deposition with potassium borohydride as reducing agent. When the deposit was heated from 10 °C to 500 °C , it took place three kinds of phase transformation and formed corresponding nickel borides. An Atomic Force Microscopy (AFM) was used to directly view the surface morphologies of the samples in various treated states. The AFM images indicate that nano dimensional protrusions grow on the surface of the deposit grain during some heat treatment processes, and they are distinguished greatly from the small bulges existing in the as plated deposit. Further studies show that the microhardness related to the surface topography of the coating to some extent. Especially when a two step heat treatment process was performed, the nano dimensional protrusions on the grain surface grew upt to 40～100 nm in diameter and 10～20 nm in height, and the deposit microhardness reached up to HV1500～1600 in the meantime.
